Performance analysis of Brillouin optical time domain reflectometry (BOTDR) employing wavelength diversity and passive depolarizer techniques

We propose and experimentally validate a wavelength diversity technique combined with a passive depolarizer in order to improve the performance of Brillouin optical time domain reflectometry (BOTDR). The wavelength diversity technique enables the maximization of the launch pump power and suppresses the nonlinear effects, the latter of which limits the conventional BOTDR performance. As a result, the signal-to-noise ratio increases, thus improving the measurement accuracy for strain and temperature. In addition, considering the complexity and expensive methods required for polarization noise suppression in BOTDR system, a simple, low-cost passive depolarizer is employed to reduce the polarization noise. The experimental results show that the signal-to-noise ratio is improved by 4.85 dB, which corresponds to 174% improvement compared to a conventional BOTDR system.